System for the transmission of data

Abstract

In an electronic system for the transmission of data between a number of stations, sub-system operation can be achieved by a suitable choice of signal levels and wake-up levels, so that some of the stations can communicate with one another while other stations are in a sleep mode in which power is saved.

What is claimed is:  
     
       1. A transmission system comprising: 
       a plurality of stations, wherein the stations have a passive mode and, in response to a wake-up signal, an active mode, in the active mode information is transmitted using at least two different voltage levels, and  
       wherein the wake-up signal is transmitted using a third voltage level which lies outside the at least two different voltage level range for the transmission of information, and allows active stations to communicate with each other without waking passive stations.  
     
     
       2. The system of  claim 1 , wherein the stations further include a bus driver to determined if a received signal is a wake-up signal by determining whether the voltage level of the received signals is outside the at least two voltage levels. 
     
     
       3. The system of  claim 1 , wherein the stations further include a means for determining if a received signal is a wake-up signal by determining whether the voltage level of the received signals is outside the at least two voltage levels. 
     
     
       4. A station for use in a transmission system having a plurality of station, the station comprising: 
       a receiver for receiving data signals, using at least two different voltage levels,  
       wherein portions of the station are switchable to a passive mode in response to a wake-up signal and enables all portions of the station to an active mode, wherein the wake-up signal is transmitted using a third voltage level which lies outside the at least two different voltage levels for the reception of information, and allows active stations to communicate with each other without waking passive stations.  
     
     
       5. The station as claimed in  claim 4 , wherein the receiver is arranged to process the wake-up signal in the same way as the signal having the voltage level nearest to the wake-up level. 
     
     
       6. The station of  claim 4 , wherein the station further includes a means for determining if a received signal is a wake-up signal by determining whether the voltage level of the received signal is outside the at least two voltage levels.